docs: def beautify_file(self, path):
          """Beautify bash script file."""
          error = False
          if(path == '-'):
              data = sys.stdin.read()
              result, error = self.beautify_string(data, '(stdin)')
              sys.stdout.write(result)
          else:  # named file
              data = self.read_file(path)
              result, error = self.beautify_string(data, path)
              if(data != result):
                  if(self.check_only):
                      if not error:
                          # we want to return 0 (success) only if the given file is already
                          # well formatted:
                          error = (result != data)
                  else:
                      if(self.backup):
                          self.write_file(path+'.bak', data)
                      self.write_file(path, result)
          return error